As is well known in the art, light-emitting diodes (“LEDs”) are more efficient than incandescent light bulbs, i.e., more light is produced per watt by an LED than by an incandescent bulb. Other known electrically-powered light sources, e.g., fluorescent light bulbs, have a number of disadvantages, as is well known in the art. For example, fluorescent light bulbs are required to be replaced relatively frequently. Where they are used in streetlights, this can involve significant expenses.
LEDs have a number of additional advantages. However, as is well known in the art, LEDs require relatively close control of voltage and current and also heat management. For example, because current through the LED is dependent exponentially on voltage, voltage should be closely controlled. Also, the voltage supplied should be sufficient, at a minimum, to cause current to flow in the proper direction (i.e., from p-type to n-type material). In addition, the ambient temperature of the operating environment can significantly affect the performance of LEDs.
Although LEDs have certain advantages when compared to incandescent or fluorescent bulbs (e.g., lower power consumption, and longer operating time) LEDs also have certain disadvantages, as noted above.